Returns 0 after saving the stack environment. If setjmp returns as a result of a longjmp call, it returns the value argument of longjmp, or if the value argument of longjmp is 0, setjmp returns 1. There is no error return.

The setjmp function saves a stack environment, which you can subsequently restore, using longjmp. When used together, setjmp and longjmp provide a way to execute a non-local goto. They are typically used to pass execution control to error-handling or recovery code in a previously called routine without using the normal calling or return conventions.

A call to setjmp saves the current stack environment in env. A subsequent call to longjmp restores the saved environment and returns control to the point just after the corresponding setjmp call. All variables (except register variables) accessible to the routine receiving control contain the values they had when longjmp was called.

It is not possible to use setjmp to jump from native to managed code.

Notesetjmp and longjmp do not support C++ object semantics. In C++ programs, use the C++ exception-handling mechanism.